Variable electric condenser, variometer, and the like



slik, F.

AND LIKE VAEJOMETER.

Fied Bec. 1924,

Cil

o ff-'ger i [van: infila-fllen Application nie/ eceniber 135342, Serial No. 754,579, and in Great Britain December 15, 1923.

rlhis invention relates to variable electric condensers` variometers and the lilro apparatus in which one member has a limited rotation relatively to another'. 'lhe object ot' thisinvention is to provide la condenser or the like wherein the effect ot' the capacity ot the operators hands when adjusting the to zero.

[recording tothe present invention'iu a variable condenser. variometer or thlike having the. shaft ot' its movable elements insulated from the operating spindle all metallic elements lying between the insulating member and the operating spindle are provided with an earth connection.

ln condensers wherein the movement ot' operating spindle is reduced lthe operating spindleis equal to the movement ot' the movable element the metallic, parts lying between the insulating member and the spindle are normally interconnected but in those condenser-s which employ gearing between the spindle andthe movable element to multiply the movement ot the one relatively to the other, it is necessary to provide means to ensure that at all times there is metallic connection between the gear members.

The invention is more particularly7 dcseribed with reference to the accompanying drawings, in which y,

Figure l shows a plan View of the instrument.

Figure lshows a further plan view .with the scale anlfinounting panel removed.

Figure 3 is an elevation ot the device.

The cond-enseucomprises in the usual manlner a pair oit' insulating plates l, 2, spaced apart b vsuitahle members such as screws 3, @and 5 which carry a set of` lined vane-s The stud further carries a terminal 7 to whi fh a conductor may be connected.

rihe rotary Yanes 8 are mounted ou a sleeve l) provided with a threaded spindle 1() and mounted at one end in a bearing 'l1 earried by) the insulating plate l.

The operating spindle 12 and handle li are displaced from the axis of the, spindle i() and connected with the same by gearing. pinion le on1 the spindle i2 meshing with a further'pinion 15 on the spindle 10. the gear ratio 'being such that on the rotation ot the movable venes 8 through 18()O Bt'rom the minimum to the maximum position the operating handlejl and spindle 12 together with the scale 16 rigidly secured thereto vvandi the metal disc 23 is have rotated through one lcomplete rcvolu tion. ln this manner the graduations ot' the, lscale may be ima'eased to double that olitainable when the scale is mounted directly 60 ou the spindle ot' the rotary members.

The pinion 15 may have teeth cut on only a portion ot' its surface as shown in Fig. 2 or alternatively may be provided with teeth completely round its periphery, the space 55 between the adjacent teeth being filled up as desired to act as stops Jfor the relative movement of the two wheels.

The mounting ot' the spindle 1()i carrying the. movable members 8 in the insulating sheet Q comprises an insulating collar 17 into which the threaded spindle 10 is screwed and afurther threaded spindle 18 projecting between the opposite end ot the insulating collar 1T and the insulating sheet 2. i Mounted on the spindle 18 isvthe gear l5 below the insulating collar 17, the latter thus completely insulating lthe gear 15 from the spindle ldand vanes 8. Mounted between the gear l5 and the insulating plate 2 is a spring washer Q0 and a strip of foil,- for example ot' copper 21.

'lhe copper strip 21 extends between the spindle 18 and the spindle 12`carrying the operating' handle 13 and is provided with a turned over portion 22 to which, if desired, an earth wire ca n be connected. In this" manner all metallic parts on the operating side ot the collar 1'7 are metallically connected.

A metal plate such as au aluminium disc 225 is mounted on the Atace ot' the panel 2l on which the condenser is mounted to avoid the effect of hand capacity, as is well known.

ln the constriwtion illustrated in Figs. l

adjustably but rigidly mounted on the panel 2d and metallically connected with the spindle 12. The disc 23 is further provided with' an indicating mark whieh'is adapted to be used as a lzeroizing indicatorl for the graduated sale iti mounted on the spindle 12.

l declare thatwhat 'I claim is:

1. In a variable electric tuning instrument, the combination' ot' a stationary coupling element, a coupling element movable relatively to said stationary element, an operating spindle having a handle for said movable element, means insulating said movable element from'said operating spindle and` con- 119 necting means adapted to connect all metallic members lying between said insulating ioa Q assises ineans and thewhanclle'ofA saicl spindleto earth.

` 2.- -n a variable eleot'ric tuning instiument the combination vof a stationary coupling element, a coupling element movable relahvelyto sa-lcl stationary element,v an operaii ing spindle having a handle for saidmovable element, means insulating said movable eleiuentfromsaid operating spindle, gears be tween said operatu'lg spindle anall said movable element and meansto interconnect sncf tallically ,at 'all 4positious of said gears, jmetallzeparts lying between said insulating elementl and the handle of said spindle.,

i 3 In a variable electric tuning instrument the combination of a stationary coupling eley ment, a coupling element movable, ielatively .to A,said stationary element, an operating spindle having handle for saicl meV-able element, means insulating said movable elenient from said operating spindle gears between said operating spinclle and said Inovableelement and means to interconneet me-r -ta1l1cal1`y at all positions of said gears all inetallic parts lying between saifl insulating elementl and the handle of salfl spindle, and

' .means on said interconnection ifneniber to attach said member to earth.

, 4. In a variable electric tuning instrument or the like electzieal .coupling device ille combination of an insulating franse,` a stationary coupling element mounted on sais, frame, a gc'otatable shaft jounallecl on said frame, a movable coupling` element 'rigidly fixed to saifl shaft, an insulating meinbei' cured to one end of sai l shaft a gear' mounted Coaxially with saiii shaft and insulated therefrom by said insnlabing niembei, an operating spindle for said movable element, a gear on saisi spindlelmesbmg With ine 4gear on said shai'igja; conductive s'tsip in metallic coniact with saiospindie anfl 'with said geai` on said shaft and means on sani I sti-ip for'an eaitll connection..

5. In a vaziable'electiic tuning insti'ument the combination of'au insulating frame, a

stationary coupling element mountecl on said ame, a rotatable shaft jouinallecl on saicl frame, a movable coupling element rigidly xed to said shaft, an insulating membei' secured to one encl of said shalt, a geen`l mounted 3o-axially with said shaft and insulated thei'efrom by said insel-ailing inem- Q ber. an oiciainfr s infile for said movable element, a gear on said spindle meshing; with the gear on said shaft, a conductive strip in metallic contact with said' spinllc and' with said gear on saisi shaft means on said strip for an eath connection au @pesas ing handle fixed to saiel operating spindle,

and a graduatedA scale rotatable 'with said spindle il lu a 14'nuiable electric tuning instrument the combination oi an insulating "frame, a

stationary coupling element mounted ou saiclA frames rotatable shaft gouinalled on said frame, a movable coupling element iigidly fixed io said shaft, an insulatingmember securerto' one enel of said shaft, a geai1 inouui'eel 'co-axially with said shai't andinsulated therefrom by said' insulating membei' an o )ei'atin s'iinfileioi' said movable 5, l. element, a gear on sani spindle meshing with the wear en saicl shaft a conductive sii-ip in metallic Contact' with said spindle and with said gear on said shai'aiueans on' said siip for an ea-iili connection, an opeiating handle iziecl-to seid operating spindle,

sulated therefrom by said. insulating mem--.

bei, an operating spindle' iol' said.` movable element, a on spin llenieshing with the gear on said` siiali, a conductive strip in metallic Contact with sairl spindle and with said gear on said shaft, means on said. strip for an saith connection, an opei'atH ing handle fixed to operating spindleq 'a raelnated seele rotatable with said sbindle and a 'ineial plate iixeil 3o said freine in metallic connection with saicl operating; spin alle and an indicating mark on said frame.

8. ln a 'variable'eleeric tuning instiument the combination oi an insulating frame a stationary coupling element ni'ounteil ou salti iframe, a i'otatable shaft joui'xiallel en said. frame, a e uplinf lenient lizietl io said shaft and movable relatively to said statief ry ele ment, an insulating member secured one end of said shaft, a geai` moun'ted coaxially wihsaul shaft insulated thei'eirom by said insulating member, an operating spin- (lie for said niovable'eiement, a geai mount-` ed, on said opezating spindle and meshing with the gear mounted on said'shait, an.

abutment-ai'iangefl on the teeth of one oi said gears' io limit the relative rotation of l'he'inmfabie membei, a eoiuluctive strip in metallic Contact with said spinrile and with said gear on said shaft and means oil saicl strip to secure an earth vconnefitlon lheieto.

in witness whereof, l have hei'eunto signed'l my name this lith slay o Novemben, 1924.

ALBERT FRAN 

